J/A+A/553/A122 Time stability of the ICRF2 axes (Lambert, 2013)
Time stability of the ICRF2 axes.
Lambert S.
<Astron. Astrophys., 553, A122 (2013)>
=2013A&A...553A.122L 2013A&A...553A.122L
ADC_Keywords: Positional data ; VLBI
Keywords: astrometry - reference systems - techniques: interferometric
Abstract:
I assess the astrometric stability of the 295 defining sources of the
current best realization of the International Celestial Reference
System (ICRS): the second realization of the International Celestial
Reference Frame (ICRF2), constructed and published in 2009 after the
analysis of millions of VLBI observations at 2 and 8 GHz between
1979.6 and 2009.2. I also assess the time evolution of the ICRF2 axis
stability.
I derived coordinate time series of hundreds of quasars monitored by
the regular geodetic VLBI program of the International VLBI Service
for Geodesy and Astrometry (IVS). The axis stability was studied by
constructing annual reference frames based on the ICRF2 defining
sources. The time variable frame stability was obtained by computing
the deformation parameters that lead from one frame to the next.
I show that, although the astrometric stability of some of the ICRF2
defining sources has slightly degraded since 2009.2, the ensemble
still constitutes a very stable reference frame. The current
estimation of the axis stability over 1979.6-2013.1 remains at the
same level as the one estimated over 1979.6-2009.2, i.e., on the
order of 20uas for each axis.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 30 295 Stability due to post-ICRF2 observations
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See also:
I/323 : International Celestial Reference Frame 2, ICRF2 (Ma+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- IVS IVS name (HHMM+DDd, B1950)
10- 13 I4 --- Nses1 Number of sessions over ICRF2 time span
(1979.6-2009.2)
15- 19 F5.3 mas Stab1 Stability over ICRF2 time span (1979.6-2009.2)
21- 24 I4 --- Nses2 Number of sessions over the full time span
(1979.6-2013.1)
26- 30 F5.3 mas Stab2 Stability over the full time span (1979.6-2013.1)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 08-Oct-2013